COMPARATIVE EVALUATION OF THE ASCORBIC ACID CONTENT OF MINERAL ASCORBATE AND ASCORBIC ACID TABLETS MARKETED IN ZARIA

COMPARATIVE EVALUATION OF THE ASCORBIC ACID CONTENT OF MINERAL ASCORBATE AND ASCORBIC ACID TABLETS MARKETED IN ZARIA, A RESEARCH PROJECT TOPIC ON BIOCHEMISTRY

ABSTRACT.

The ascorbic acid content of mineral ascorbate and six brands of ascorbic acid tablets marketed in Zaria with brand names Calcium ascorbate, Ascorbion, Emvit C, Ascorvite, Topcee, Bioracee and Sofa C respectively were comparatively evaluated using four methods. These include titrimetric method of British pharmacopoiea 2009, sodium thiosulphate titrimetric method, Ultra violet spectrophotometric method employing stabilizers and a newly developed 2,4-dinitrophenyl hydrazine method. The developed method was validated and the analyte showed an absorption maxima at 527nm and a percentage recovery of 97.4%. Beer‘s law was obeyed in the concentration range of 5ug to 25ug/ml, giving a regression equation of y= 0.041x + 0.032 and a correlation coefficient of 0.9910. The percentage content of ascorbic acid in Calcium ascorbate, Ascorbion, EmvitC, Ascorvite, Topcee, Bioracee, and SofaC in the Ultra violet spectroscopy method using stabilizers were 108.2%, 29.7%, 26.3%, 33%, 66.7%, 46.7%, 27.948% respectively. The values obtained from the sodium thiosulphate titrimetric method were 95.6%, 98.30%, 101.90%, 94.86%, 94.18%, 98.89% and 100.02% respectively. The results obtained from the B.P 2009 titrimetric method were 100.58%, 102.49%, 108.51%, 100.12%, 79.29%, 102.05% and 104.84% respectively, while that of the modified 2,4-dinitrophenyl hydrazine method were 100.47%, 101.99%, 107.898%, 99.83%%, 78.02%, 101.97%, 104.96% respectively. These results obtained showed that the UV spectrophotometric method gave values below the normal range. The values from the sodium thiosulphate titrimetric method was within the normal range but does not compare favourably with the official method, whereas the values for the modified 2,4 dinitrophenylhydrazine method and that of the B.P 2009 titrimetric method were both within the normal range and compared favourably with each other. Both results subjected to Student‘s T-testing showed no significant difference at P value 95% confidence interval (p=0.05). The B.P 2009 titrimetric method showed that there is one substandard product, which is Sofa C on the basis that it has a percent label claim not within 90±5%. The findings of this work further showed that the newly modified method can be used as a substitute for the official method.

CHAPTER ONE

INTRODUCTION

1.1    ASCORBIC ACID

Vitamin C otherwise known as ascorbic acid is a water soluble vitamin that is naturally present in some foods, added to others and taken as a dietary supplement. Though it is derived from glucose, humans and some other primates like guinea pigs, teleost, fishes, bats and birds cannot synthesize it invivo due to the genetic mutation that prevents them from synthesizing L-gluconolactone oxidase enzyme, which converts glucose to ascorbic acid. Vitamin C can be synthesized by some other animals like dogs, goats, sheep, etc. (Storn, 1972).

Vitamin C is an important component of a healthy diet. Its history revolves around that of the human scurvy disease; a severe form of vitamin C deficiency, probably the first human sickness to be recognized as a deficiency disease. Its symptoms includes exhaustion, massive haemorrhaging of flesh and gums, general weakness and diarrhoea. Presently, it is rare to be seriously deficient of vitamin C, although evidence suggests that many people may have low levels of Vitamin C. Smoking cigarettes lowers the amount of vitamin C in the body. Smokers are therefore at a higher risk of its deficiency. (retrievded from national institute of health, United States). Vitamin C is needed for the growth and repair of tissues in all parts of the body. It helps the body make collagen; an important protein used to make skin, cartilage, tendons, ligaments and blood vessels. It is also needed for healing of wounds and maintenance of bones and teeth.(Briggs, 1981).

COMPARATIVE EVALUATION OF THE ASCORBIC ACID CONTENT OF MINERAL ASCORBATE AND ASCORBIC ACID TABLETS MARKETED IN ZARIA, A RESEARCH PROJECT TOPIC ON BIOCHEMISTRY